What is Article 4.2? Who is in the Umbrella group?

Hydrofluorocarbon. An atmosphere-warming greenhouse gas, used for refrigeration and air conditioning. HFCs are also used as foam blowing agents, solvents, fire fighting agents and aerosol propellants. HFCs were introduced by the chemical industry to replace ozon-destroying CFCs (and HCFCs), and are know as "super greenhouse gases" since their soaring use and high global warming potential (GWP) could offset the benefits from reducing other greenhouse gases (GHGs) such as carbon dioxide. HFCs make up only a small share of GHG emissions, but they are extremely powerful GHGs. (see also CFC, CO2 and PFC)